Tube drawing apparatus



March 13, 1934. c. H. WALLIS TUBE DRAWING APPARATUS Filed Feb, 3, 1932 3Sheets-Sheet 1 March 13, 1934. Q w

TUBE DRAWING APPARATUS Filed Feb. 3. 1932 3 Sheets-Sheet 2 N Maw @6 02:CLHEE/VCE H. WQLL/S,

March 13, 1934.

c. H. WALLIS TUBE DRAWING APPARATUS 3 Sheets-Sheet 3 Filed Feb. 5. 1932Patented Mar. 13, 1934 UNITED STATES TUBE DRAWING APPARATUS Clarence H.Wallis, Ellwood City, Pa., assignor to National Tube Company, acorporation of New Jersey Application February 3, 1932, Serial No.590,682

3 Claims.

This invention relates to tube drawing appa ratus, and more particularlyto automatically operated pliers for tube drawing benches, and has forits object the provision of a plier or tube gripping mechanism whichwill automatically grip the pointed endof the tube to be drawn and willautomatically disengage from the tube when the tube has been completelydrawn through a reducing die.

In the drawings:

Figure 1 is a fragmentary side elevation of a draw bench showing thepliers of this invention with its draft hook free of the draw benchchain.

Figure 2 is a similar view showing the pliers immediately after thedraft hook has been automatically dropped into engagement with the drawbench chain.

Figure 3 is a similar view showing the pliers with the draw bench chainunder draft tension.

Figure 4 is a plan view of the apparatus positioned as shown in Figure3.

Figure 5 is a fragmentary side elevation of a draw bench showing amodified form of pliers with its draft hook engaged in the draw benchchain while said chain is under draft tension.

Referring more particularly to the drawings, the numeral 1 designatesthe draw bench chain, which is of usual construction and is propelledalong the draw bench in the usual manner by a motor reduction unit (notshown). The pliers or tube gripping device is designated generally bythe numeral 19 and comprises a wheeled carriage adapted to travel alongsuitable trackways 19 on the draw bench and is provided with a hook 2which is adapted to be engaged in the chain 1. The hook 2 is adapted tobe held in elevated position above the chain 1 by a latch 22 whichengages a lug 2 as shown in Figure 1, when the pliers are out ofengagement with a tube to be drawn and while the pliers are beingreturned to the die end of the bench. The hook 2 is provided with an arm3 which is connected by an adjusting rod 4, compression spring cylinder5 and plunger rod 28 with a lever arm 23 fixed on a shaft 6 whichcarries a pair of levers 24 for a purpose to be described. A pair ofgripping jaws 7 is slidably mounted in the pliers carriage for movementin a direction parallel to the longitudinal axis of the carriage, andhave their side faces opposite their gripping faces beveled and incontact with inclined surfaces in the carriage body so that they willmove toward or away from each other when they are moved in a directionparallel with the longitudinal axis of the carriage.

The levers 24 are adapted to engage the rear ends of the jaws 7 when thehook 2 is disengaged from the latch 22 and drops down into 0 engagementwith the chain 1 so as to force the jaws forwardly along the inclinedfaces in the pliers carriage, thereby causing said jaws to move towardeach other and grip the pointed end of the tube to be drawn.

In the drawings, the head block or die holder is designated by thenumeral 9, and the tube to be drawn is designated by the numeral 8.

A latch release rod 25 is slidably mounted along the top of the plierscarriage and is provided with a head 26 which is adapted to engage orstrike the head block 9 when the carriage is moved into tube engagingposition and as the head 26 of the rod 25 engages the head block 9 therod 25 will move rearwardly and engage a lug 22 on the latch 22, therebyrocking said latch upwardly and disengaging the hook 2.

The carriage is adapted to be moved rearwardly along the draw bench bymeans of a cable 12 which is trained over suitable sheaves 11 and 21 andis given several wraps around a drum 13 and has its end anchored to aleg 20 secured to the carriage 19 of the pliers. The drum 13 is adaptedto be operated by a motor 18 and gear reducing unit 14. The drive shaft15 of the gear reducing unit 14 is connected by a flexible coupling 16to the power shaft 1'7 of the motor 18.

It is advantageous for the plier grips or jaws 7 to take hold of thepoint end of the tube prior to the start of the reduction pass. At theend of the reduction pass it is advantageous for the plier grips 7 toimmediately release the point end of the tube. The downward travel ofthe plier hook 2 actuates the levers 24 and provides a means forautomatically moving the jaws or grips 7 forwardly into grippingengagement with the point end of the tube prior to the. start of thereduction pass. The compression spring in the cylinder 5, in conjunctionwith the plunger 100 rod 28, provides a means for compensating for pointends of varying diameters, allowing the plier hook 2 to drop asufficient distance to engage the draw chain 1 regardless of thediameters of the point end within operating limits.

The levers 24, which are actuated by the dropping of the plier hook 2,move the plier grips or jaws '7 forwardly an equal amount so as to causeequal gripping or engagement of the point end of'the tube.

After the jaws or grips '7 have gripped the pointed end of the tube 8and the hook 2 has dropped into engagement with the chain 1 the tensionor pull of the chain 1 against the hook will cause the hook to rock,about its pivotal connection and rise up into the position shown inFigure 3. This upward movement of the hook 2 under pull of the chain 1will rock the lever 23 and levers 24 so as to move the levers 24rearwardly clear of the jaws or grips 7 so as to permit said jaws tohave free movement for disengagement from the point end of the tubeafter the tube has been completely drawn through the reducing die. Thepliers 19 and the tube 8 will travel at a predetermined drawing speedduring the reduction pass. Immediately after the reduction pass thetremendous pull which is exerted on the drawing mechanism during thereduction pass causes the tube 8 and pliers 19 to coast or run forwardahead of the chain 1 sufllciently to permit the chain 1 to drop ordisengage from the hook 2 and, therefore, allows the hook to drop towardthe chain 1 until the latch 22 again engages the lug 2* of the hook 2.

As stated before, during the drawing or reducing pass the hook 2 andchain 1 are forced upwardly by the tension or pull of the draw chain andthe'hook 2 is positioned so that the latch 22 is supported on the hookimmediately forward of the lug 2 and, therefore, is in position toengage the lug 2 when the hook is freed from the chain 1. The positionof the hook 2 and latch 22 while the hook is suspended above the chain 1is shown clearly in Figure 1, and the position of the hook immediatelyafter it is disengaged by the latch 22 and prior to the application offorce by the draw chain 1 is shown clearly in Figure 2.

During the reduction pass of the apparatus the motor 18 is deenergizedand the forward movement of the pliers 19 will be communicated throughthe cable 12 and reducing gearing 14 to the motor 18 so as to operatethe motor 18 in the reverse direction.

This operation of the reduction gearing and motor 18 in reversedirection serves as a brake the pliers 19 when the tube 8 and pliers 19move forwardly will cause the momentum of the tube to be exerted on thegrips or jaws 7 and will, therefore, move said jaws rearwardly along theinclined surfaces of the carriage 19 so as to release said jaws or gripsfrom the point end of the tube 8.

In Figure 5 I have shown a modified form of pliers 19 in which the latch22 is provided with retaining lugs 30 and 31 for holding the draft hook2 of the pliers in elevated position. In the previously described plierconstruction the latch 22 is provided with a single lug or catch. Whenthe pliers are under draft tension the draft hook 2 is forced upwardlyan amount depending on the amount of draft tension. In the priordescribed construction, therefore, the latch 22 must have its catch lugpositioned so as to be beyond the lug 2' of the hook 2 when the minimumdraft is applied to the pliers. when the maximum draft is applied to thepliers previously described, the latch 22 will be positionedsubstantially as' shown in Figure 3. when in this position considerablefree movement of the hook 2 takes place when the hook is disengaged fromthe chain. 1 prior to the engagement of the lug 2' with the catch lug ofthe latch 22.

In some instances this free movement of the hook 2 may be injurious tothe latch. Thereforce, I have provided the modified form of latch ofFigure 5 in which the lugs 30 and 31 are provided for engaging the lug2* of the hook when said hook is elevated the minimum and maximumamounts, respectively. The latch lug 31 is positioned so as to engagethe lug 2 of the hook at some point intermediate the minimum and maximumelevation of the hook 2 and serves to reduce the free movement of thehook materially.

While I have shown and described one specific form of my invention, itwill be understood that I do not wish to be limited thereto, sincevarious modifications may. be made without departing from the scope ofmy invention, as defined in the appended claims.

I claim:

1. In a tube drawing bench, ahead-block and die, a draw chain, plierscomprising a carriage, means for returning said carriage toward saidhead-block, a hook provided with a lug mounted on said carriage andadapted to be engaged with said draw chain, a latch for engaging the lugon said hook to hold said hook out of engagement with said chain, a lugon said latch,

a rod movably mounted on said carriage and having one of its endsadapted to engage the lug on said latch, and the other end of said rodbeing positioned for engagement with said head-block.

2. In a tube drawing bench, a head-block and die, a draw chain, plierscomprising a carriage, means for returning said carriage toward saidhead-block, a hook provided with a lug mounted on said carriage andadapted to be engaged with said draw chain, plier grips slidably mountedin said carriage for a combined movement longitudinally of said carriagetoward and away from each other, a latch for engaging the lug on saidhook to hold said hook out of engagement with said draw chain, a lug onsaid latch, a rod mounted for sliding movement on said carriage, one endof said rod being adapted to engage the lug on said latch and the otherend of said rod being positioned to contact with said headblock.

3. In a draw bench, the combination of a die head, a drawing carriagemovable with respect to said die head, an endless chain, a connectinghook mounted on said carriage and adapted to engage with said chain, apawl adapted to hold said hook in inoperative position, and a rodmounted in said carriage, one end of said rod adapted to contact withthe face of said die head, the other end being adapted to trip saidpawl. I

CLARENCE H. WALLIS.

